1. Field of the Invention
The present invention is directed to a method for imaging a quality of service feature available in a connection-oriented communication network and that distinguishes a high-priority data stream from a low-priority data stream into a connectionless communication network and vice versa.
2. Description of the Related Art
A local area network, referred to as a LAN below, is known from Gerd Sigmund, Grundlagen der Vermittlungstecnik. In a LAN, data is transmitted by the transport of data packets (data of limited length). The data packets contain a source address and a destination address and are spontaneously sent, i.e. without a previous connection setup (connectionless communication).
A quality of service feature references one option from a plurality of possible options that are characteristic of a given communication network. What is thereby understood, for example, is an operating mode or an additional service of the communication network. One quality of service feature in the ATM network is the identifier for the transmission of a high-priority data stream, i.e. of a data stream that requires a secure transmission (see below) according to specific criteria (see below), as distinguished from a low-priority data stream that, accordingly, does not require a secure transmission.
What is to be understood by a transparent transmission or, respectively, a transparent data stream is a transmission or a data stream whose content is transmitted without an analysis. The conversion of the content into control information and data only ensues in the destination system. This corresponds to the view of the OSI layer model according to the ISO definition (ISO=International Standardization Organization) which is familiar to a person skilled in the art. A layer-by-layer view is also expedient and standard in the framework of communications technology beyond the OSI layer model.
Gerd Sigmund, Grundlagen der Vermittlungstechnik discloses an ATM network (ATM=asynchronous transfer mode). The ATM network works connection-oriented, i.e. the data transmission is composed of a connection setup, of an information transmission and a connection cleardown. Further details can be derived from the above mentioned publication and numerous other sources as well as the corresponding standards.
It is known to connect a LAN, for example as an Ethernet or a Token Ring, to an ATM network. Prescribable changes in the definition of the LAN are to be thereby undertaken; in this context, one speaks of a LAN emulation, also referred to as LANE. Let the corresponding LANE definition of the xe2x80x9cATM Forumxe2x80x9d be referenced for farther-reaching information (see ATM Forum: LAN Emulation over ATM V1.0, ATM Forum LANE-0021.00).
The LANE described in the publication ATM Forum: LAN Emulation over ATM V1.0, ATM Forum LANE-0021.000 has the disadvantage that no use of the quality of service features (QoS) defined in the ATM network is possible. Since such quality of service features are likewise not available in the connected LANs, for example the Ethernet, there is no possibility of different handling of data streams, i.e. of a distinction between low-priority and high-priority data streams, as is standard in the ATM network.
However, it is possible to expand the existing LANE or the traditional LAN as well to the effect that such a discrimination into low-priority and high-priority data streams can be made. Such an expansion can be derived from the international patent application PCT/DE97/00404 filed 4 Mar. 1997 and shall be summarized again below. Such an expanded LAN is referred to below as LANE2.
Up to now, the quality of service features have been lost at every transition between a LANE2 and an ATM network.
An object of the present invention is comprised in imaging a quality of service feature available in a connection-oriented communication network, namely the discrimination between a high-priority and a low-priority data stream, into a connectionless communication network and vice versa.
This object is achieved by a method for imaging a quality of service feature available in a connection-oriented communication network that identifies a high-priority data stream or a low-priority data stream into a connectionless communication network and vice versa,
a) whereby a first, low-priority data stream from the connection-oriented communication network is transparently imaged into the connectionless communication network;
b) whereby a first high-priority data stream from the connection-oriented communication network is transparently imaged into the connectionless communication network;
c) whereby a second low-priority data stream from the connectionless communication network is imaged in to the connection-oriented communication network, whereby an address conversion of an address of the connectionless communication network into an address of the connection-oriented communication network is implemented;
d) whereby a second-priority data stream from the connectionless communication network is imaged into the connection-oriented communication network, in that when the second high-priority data stream is a matter of a signaling packet, a conversion of a signaling information of the signaling packet from the connectionless communication network into a signaling information available in the connection-oriented communication network is implemented, and when the second high-priority data stream is a matter of an information packet, a transparent transmission into the connection-oriented communication network is implemented.
The present invention images a quality of service feature available in a connection-oriented communication network into a connectionless communication network. The aforementioned ATM network is an example of a connection-oriented communication network, and likewise afore-mentioned LANE with a corresponding expansion is an example of a connectionless communication network.
A first low-priority data stream or a first high-priority data stream is transmitted transparently from the connection-oriented communication network into the connectionless communication network. A second low-priority data stream is transmitted from the connectionless communication network into the connection-oriented communication network, whereby an address conversion of an address of the connectionless communication network into an address of the connection-oriented communication network is implemented. A second high-priority data stream is imaged from the connectionless communication network into the connection-oriented communication network in thatxe2x80x94when the second high-priority data stream is a signalling packetxe2x80x94a conversion of a signalling information of the signalling packet from the connectionless communication network into a signalling information available in the connection-oriented communication network is implemented orxe2x80x94when the second high-priority data stream is a matter of an information packetxe2x80x94a transparent transmission into the connection-oriented communication network is implemented.
A first development of the invention describes the conversion of quality of service parameters that are available in the connectionless communication network into the connection-oriented communication network in the following steps:
a suitable bandwidth for a new connection is defined from the available bandwidth;
an appertaining address of the connection-oriented communication network is defined from the address of the connectionless communication network by an address conversion;
the connection is set up when a suitable bandwidth is available and the address of an appertaining subscriber in the connection-oriented communication network is known.
Another development is comprised therein that the connection-oriented communication network is an ATM network and the address of the connection-oriented communication network is an ATM address.
An additional development is comprised therein that the connectionless communication network is a LAN, whereby the address of the connectionless communication network is a LAN address. This LAN corresponds to the initially cited version LANE2 expanded by the high-priority/low-priority quality of service feature.
A next development is comprised in the embodiment of the address conversion (from the LAN into the ATM network). An ATM address is found for a prescribable LAN address in that either the LAN address is available on a LANE server or via specifically set up connections to all neighboring nodes.
Developments of the invention provide that the quality of service parameter available in the connectionless communication network from the signaling packet is converted into the connection-oriented communication network in the following steps:
a) a suitable bandwidth from the total bandwidth available is defined for a new connection;
b) the suitable address of the connection-oriented communication network is defined from the address of the connectionless communication network on the basis of an address conversion;
c) when a suitable bandwidth is available and when the address is known in the connection oriented communication network, the new connection is set up;
d) when no suitable bandwidth is available or when the address is unknown in the connection-oriented communication network, then a prescribable error message is displayed.
An additional improvement provides that the connection-oriented communication network is an ATM network and the address of the connection-oriented communication network is an ATM address. The connectionless communication network may also be a local area network (LAN) that is expanded by the quality of service feature of being able to distinguish between a high-priority and a low-priority data stream, and the address of the connectionless communication network is an LAN address. In these, the address conversion is implemented in the following steps:
a) the ATM address for the LAN address is determined by an LAN server or
b) when the ATM address is not locally available, an inquiry is implemented at an ATM server, whereby the ATM address is communicated from the ATM server as reply.